The present invention concerns a process for the control of a component of a textile machine as well as concerning an apparatus for the execution of the process.
In the case of modern textile machines, the customary practice is to provide components for the control of the complex process at each workstation. These components themselves, are controlled with the aid of individual regulators which in turn are in communication through a bus system with an over-all control center (EP 0 385 530 A1). This known arrangement has the capability of controlling the startup of the components of a workstation as well as correcting such faults as arise. During the operation of a textile machine, long or short term power failures from various causes can occur, and the machine is deprived of the current necessary to carry on an orderly operation.
It is therefore a principal object of the present invention to create a process and an apparatus of such a nature that the flow of production need not be cut off or shutdown during short term power failures. In accord with an additional purpose, it is also desirable that, following longer voltage losses or breakdowns, the workstations can be restored to operation in the shortest possible time. Additional objects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
The principal purpose is achieved by presetting specified speeds of rotation of a component of a textile machine workstation and presetting a time period for the deceleration of the various components. The speeds of the components during this deceleration can be maintained in a defined sequential manner, while the required relative speeds are retained at such a level that an orderly operation remains possible. By this means, the produced material, for instance, a yarn, does not deteriorate in quality.
If, before the expiration of the specified time period, the necessary voltage is restored, then the components in a controlled or regulated manner come back up to their operational speeds without the necessity of taking an operational interruption. This corrective action assures, that the relative speeds of the components among each other necessary for an orderly production always remain in effect not only during a reduction of speed, but also during a subsequent acceleration.
Advantageously, the period of time, during which the speed reduction takes place in a controlled manner, is specified to endure generally up to 3 seconds and/or is determined with dependency on the first set speed.
In order to assure, that, independent of their individual inertias, the components can accelerate properly, it is an advantage, if, within the invented formulation of the present process, the acceleration does not occur from a constant speed phase, until after a delay for constant speed conformation is established by all components. This task is accomplished by having the component, for a second specified time period, driven at essentially constant speed, before it is accelerated in a controlled or regulated manner to the first set speed.
The auxiliary current supply, which is delivered during a short-time power loss for the purpose of bridging over the no-current spell, can be produced for a short, determined time from the momentum of the still running textile machine. Thus, those components, which determine or influence the loss of the products produced on the machine during the power drop outxe2x80x94the products being, for instance, a fiber band or a yarnxe2x80x94hold the products in a desirable speed relationship to each other. The momentum, which serves as this auxiliary energy source, loses more and more energy, i.e., speed, as the power loss continues. Thus, such a current can be maintained only for a short period, and is designated for control and drive of each component, which component contributes to an essentially unchanged product. In accord with the invention, upon the expiration of a first period, during which the components in a controlled or regulated manner are slowed in rotational speed, then the components with the greatest speed are brought to a stop by running without control or they are braked. This allows the textile machine to be brought in the quickest way into a state from which it can be started up again in a controlled or regulated manner. Besides relying on the momentum, for instance, the auxiliary energy can be made available by batteries or by a lagging motor of the system or by a neighboring machine acting as yet another auxiliary energy source.
In accord with the invention, an apparatus serves for the execution of the described process. A voltage monitor continually checks the voltage of the current supplied by the utility network and signals the control system of any deviation from the specified voltage, so that the control equipment can react immediately to a loss of voltage, and the components can wind down in a controlled fashion. The two set RPM""s provide the range of the speed of rotation, which must continue through the span of time set by the control input. In this way, the speed curve from component to component can vary. The manner, that is, the downward curve, of the speed reduction is determined in dependency on the chosen set rotational speeds by a program which was previously input into the control apparatus.
When the required voltage is again available, then an acceleration of the components is introduced. If the full voltage is restored before the preset shutoff time is reached, then the components are accelerated in a controlled or regulated way, so that the properties of the produced products are not changed. In order to provide a mutual accommodation phase to the components to be accelerated, and to give them sufficient time to be able to follow the acceleration independent of their inertial delay in the required manner, a time-control mechanism is advantageously constructed. The time-control mechanism insures the components are driven at a constant speed until full voltage is restored and that the components are accelerated in a controlled or regulated manner to the first speed of normal operations.
If the prescribed time interval has run out, then the speeds, such as were required for a proper production, can no longer be maintained. A reacceleration of the components now has no point, since the required speed ratio between the individual components has been destroyed, even if the required voltage had been renewed. In order to once again be able to bring the production up in an orderly manner, the invention provides that the components first are brought to a stillstand as quickly as possible, so that the combination of the components can be accelerated from the stillstand and brought up to production speed in a regulated manner.
If the components and the individual or central control apparatuses are connected together by a field bus-system, then a very rapid and simple communication between one another by means of data exchange is possible.
If one or more or the components signal to the individual or central control apparatus that certain conditions, such as, the achievement of a specified rate of rotation or a set rotational ratio to other components has been met, then a particularly uniform and rapid acceleration of the components can be achieved.
The present invention enables, in a more simplified way, the reduction of the idle time periods of the textile machines of the previously mention type. This reduction is achieved by short time failures of voltage not leading immediately to shutdown of the machine. Rather, the machine is caused to carry on with production, even at a declining speed as long as a specified time interval is not overstepped. This declined speed of production continues until the components regain their normal operational speed either by renewed application of the required voltage or the components are brought to the idle state as quickly as possible upon continued absence of voltage. In the latter circumstance, the components are prepared to be immediately set into operational performance in the usual manner when current is once again available.
Embodiments of the invention are described and explained in greater detail with the aid of drawings.